Timing weight loss: It’s not just what we eat but when we eat, say researchers

Timing could be a missing element in weight management efforts, say researchers

The regulation of weight loss is not simply dictated by the balance between energy intake and expenditure, but rather requires correctly timed food delivery, according to new research.

New research has brought a new player to the weight loss equation – timing. The study, published in the International Journal of Obesity, suggests that while most weight loss plans and products focus on providing nutritionally balanced foods that help to reduce energy intakes, the industry could be missing a key factor in weight loss success by failing to add timing recommendations.

Led by Professor Marta Garaulet from the University of Murcia, Spain, the research international research team noted that there is emerging evidence to suggest a direct relationship between the timing of food intake and mechanisms of weight regulation.

"However, whether the timing of food intake influences the success of a weight-loss diet in humans is unknown," they said.

"This is the first large-scale prospective study to demonstrate that the timing of meals predicts weight-loss effectiveness," explained senior author of the study Dr Frank Scheer from Brigham and Women's Hospital, USA. "Our results indicate that late eaters displayed a slower weight-loss rate and lost significantly less weight than early eaters, suggesting that the timing of large meals could be an important factor in a weight loss program."

"This study emphasizes that the timing of food intake itself may play a significant role in weight regulation" he said.

Garaulet added that the findings emphasize that timing of food intake plays a significant role in weight regulation, adding that future products aimed at the weight management market should consider "not only the caloric intake and macronutrient distribution, as it is classically done, but also the timing of food."

Study details

The research team evaluated how the timing of food intake impacts weight management in a sample of 420 Spanish participants who followed a 20-week weight-loss program.

The participants were grouped as either ‘early eaters’ or ‘late eaters’ depending on the timing of consumption of their main meal – which in this population is lunch. An early lunch was defined as consumption before 3pm (51% of the subjects were early eaters) while a late lunch was counted as food intake after 3pm (49% of participants).

Garaulet and her colleagues found those consuming a late lunch lost significantly less weight and displayed a significantly slower weight-loss rate during the 20 weeks than early eaters.

"Surprisingly, energy intake, dietary composition, estimated energy expenditure, appetite hormones and sleep duration was similar between both groups. Nevertheless, late eaters were more evening types, had less energetic breakfasts and skipped breakfast more frequently that early eaters (all; P<0.05)," wrote the team.

They also reported that the timing of the other smaller meals did not play a role in the success of weight loss.

Garaulet and her team also examined other traditional factors that play a role in weight loss – such as total calorie intake and expenditure, appetite hormones leptin and ghrelin, and sleep duration. Among these factors, they report finding found no differences between both groups – so suggesting that the timing of the meal was an important and independent factor in weight loss success.